Laser Direct Imaging (LDI) is a maskless photolithography technology. Different from the conventional way that needs for the mask process method, using the maskless photolithography process to produce printed circuit boards (PCBs) may achieve higher precision, and provide greater flexibility in production.
The laser direct imaging technology is laser depicted on the circuit board one by one based on the patterns to be imaged on the circuit board. So in order to enhance the speed of circuit board production, the laser direct imaging technology usually configures with a plurality of laser light sources and a plurality of polygon mirrors, which depict the patterns to be imaged on the circuit board simultaneously by the plurality laser sources.
However, when a plurality of high-speed rotating polygon mirrors rotate in the same direction at the same time, a resonance phenomenon occurs, thereby causing the problem of imaging blur.